I inserted a tampon fo the first time today, but after wards I almost passed out!

you could have been nuerve's, just keep trying... practice makes perfect.

I do not wear tampons cause I don't like the way they feel but what I do know on the back of the box there is warning signs there is this condition that could be deadly and the fact that you got dizzy is a sure sign that you might need to stop using them and just switch to maxi pads, just read the back of the box it will tell you all about it.

That's perfectly normal my sister had the same problem

use a diffrent brand the best is u by koltex